Clinical tests are critical to diagnosis and treatment of various diseases. Many chronic diseases can usually be detected by various diagnostic assays long before pathological symptoms are manifested. Indeed, many intractable diseases, such as various forms of carcinoma, can be cured or controlled if detected at an early stage. To this end, individuals are advised to undergo regular professional physical examinations and to perform routine self-examinations. The diagnostic and prognostic value of self examinations are greatly enhanced if interpreted along with analytical assays of disease markers in biological samples, such as saliva, urine, vaginal secretion, sweat, and feces, collected by a patient at home. It is therefore of the utmost importance that biological samples be collected in a manner that is safe for the patient yet will assure the stability of the samples for analysis.
Many strategies have been developed to extract molecular information present in extremely complicated biological samples, such as blood and cell lysates. Most commonly, these involve very time-consuming pre-separation of the mixture into individual analyzable components, e.g. by 2D-PAGE. However, with the advancement of mass spectrometric (MS) techniques, a moderately complicated mixture can be successfully analyzed without prior isolation of individual components. This type of rapid analysis of complex biological samples is particularly valuable in clinical bioanalysis. Thus there is an ongoing need for methods that allow safe, easy, and reliable collection of biological samples by patients themselves on the one hand, and fast separation of crude samples into MS-analyzable fractions on the other.